includes/libs/rdbms/lbfactory/LBFactory.php

   1 <?php
   2 /**
   3  * Generator and manager of database load balancing objects
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  18  * http://www.gnu.org/copyleft/gpl.html
  19  *
  20  * @file
  21  * @ingroup Database
  22  */
  23
  24 namespace Wikimedia\Rdbms;
  25
  26 use Psr\Log\LoggerInterface;
  27 use Wikimedia\ScopedCallback;
  28 use BagOStuff;
  29 use EmptyBagOStuff;
  30 use WANObjectCache;
  31 use Exception;
  32 use RuntimeException;
  33
  34 /**
  35  * An interface for generating database load balancers
  36  * @ingroup Database
  37  */
  38 abstract class LBFactory implements ILBFactory {
  39         /** @var ChronologyProtector */
  40         protected $chronProt;
  41         /** @var object|string Class name or object With profileIn/profileOut methods */
  42         protected $profiler;
  43         /** @var TransactionProfiler */
  44         protected $trxProfiler;
  45         /** @var LoggerInterface */
  46         protected $replLogger;
  47         /** @var LoggerInterface */
  48         protected $connLogger;
  49         /** @var LoggerInterface */
  50         protected $queryLogger;
  51         /** @var LoggerInterface */
  52         protected $perfLogger;
  53         /** @var callable Error logger */
  54         protected $errorLogger;
  55         /** @var callable Deprecation logger */
  56         protected $deprecationLogger;
  57         /** @var BagOStuff */
  58         protected $srvCache;
  59         /** @var BagOStuff */
  60         protected $memStash;
  61         /** @var WANObjectCache */
  62         protected $wanCache;
  63
  64         /** @var DatabaseDomain Local domain */
  65         protected $localDomain;
  66         /** @var string Local hostname of the app server */
  67         protected $hostname;
  68         /** @var array Web request information about the client */
  69         protected $requestInfo;
  70
  71         /** @var mixed */
  72         protected $ticket;
  73         /** @var string|bool String if a requested DBO_TRX transaction round is active */
  74         protected $trxRoundId = false;
  75         /** @var string|bool Reason all LBs are read-only or false if not */
  76         protected $readOnlyReason = false;
  77         /** @var callable[] */
  78         protected $replicationWaitCallbacks = [];
  79
  80         /** @var array[] $aliases Map of (table => (dbname, schema, prefix) map) */
  81         protected $tableAliases = [];
  82         /** @var string[] Map of (index alias => index) */
  83         protected $indexAliases = [];
  84
  85         /** @var bool Whether this PHP instance is for a CLI script */
  86         protected $cliMode;
  87         /** @var string Agent name for query profiling */
  88         protected $agent;
  89
  90         private static $loggerFields =
  91                 [ 'replLogger', 'connLogger', 'queryLogger', 'perfLogger' ];
  92
  93         public function __construct( array $conf ) {
  94                 $this->localDomain = isset( $conf['localDomain'] )
  95                         ? DatabaseDomain::newFromId( $conf['localDomain'] )
  96                         : DatabaseDomain::newUnspecified();
  97
  98                 if ( isset( $conf['readOnlyReason'] ) && is_string( $conf['readOnlyReason'] ) ) {
  99                         $this->readOnlyReason = $conf['readOnlyReason'];
 100                 }
 101
 102                 $this->srvCache = isset( $conf['srvCache'] ) ? $conf['srvCache'] : new EmptyBagOStuff();
 103                 $this->memStash = isset( $conf['memStash'] ) ? $conf['memStash'] : new EmptyBagOStuff();
 104                 $this->wanCache = isset( $conf['wanCache'] )
 105                         ? $conf['wanCache']
 106                         : WANObjectCache::newEmpty();
 107
 108                 foreach ( self::$loggerFields as $key ) {
 109                         $this->$key = isset( $conf[$key] ) ? $conf[$key] : new \Psr\Log\NullLogger();
 110                 }
 111                 $this->errorLogger = isset( $conf['errorLogger'] )
 112                         ? $conf['errorLogger']
 113                         : function ( Exception $e ) {
 114                                 trigger_error( get_class( $e ) . ': ' . $e->getMessage(), E_USER_WARNING );
 115                         };
 116                 $this->deprecationLogger = isset( $conf['deprecationLogger'] )
 117                         ? $conf['deprecationLogger']
 118                         : function ( $msg ) {
 119                                 trigger_error( $msg, E_USER_DEPRECATED );
 120                         };
 121
 122                 $this->profiler = isset( $conf['profiler'] ) ? $conf['profiler'] : null;
 123                 $this->trxProfiler = isset( $conf['trxProfiler'] )
 124                         ? $conf['trxProfiler']
 125                         : new TransactionProfiler();
 126
 127                 $this->requestInfo = [
 128                         'IPAddress' => isset( $_SERVER[ 'REMOTE_ADDR' ] ) ? $_SERVER[ 'REMOTE_ADDR' ] : '',
 129                         'UserAgent' => isset( $_SERVER['HTTP_USER_AGENT'] ) ? $_SERVER['HTTP_USER_AGENT'] : '',
 130                         'ChronologyProtection' => 'true',
 131                         'ChronologyPositionIndex' => isset( $_GET['cpPosIndex'] ) ? $_GET['cpPosIndex'] : null
 132                 ];
 133
 134                 $this->cliMode = isset( $conf['cliMode'] ) ? $conf['cliMode'] : PHP_SAPI === 'cli';
 135                 $this->hostname = isset( $conf['hostname'] ) ? $conf['hostname'] : gethostname();
 136                 $this->agent = isset( $conf['agent'] ) ? $conf['agent'] : '';
 137
 138                 $this->ticket = mt_rand();
 139         }
 140
 141         public function destroy() {
 142                 $this->shutdown( self::SHUTDOWN_NO_CHRONPROT );
 143                 $this->forEachLBCallMethod( 'disable' );
 144         }
 145
 146         public function shutdown(
 147                 $mode = self::SHUTDOWN_CHRONPROT_SYNC, callable $workCallback = null, &$cpIndex = null
 148         ) {
 149                 $chronProt = $this->getChronologyProtector();
 150                 if ( $mode === self::SHUTDOWN_CHRONPROT_SYNC ) {
 151                         $this->shutdownChronologyProtector( $chronProt, $workCallback, 'sync', $cpIndex );
 152                 } elseif ( $mode === self::SHUTDOWN_CHRONPROT_ASYNC ) {
 153                         $this->shutdownChronologyProtector( $chronProt, null, 'async', $cpIndex );
 154                 }
 155
 156                 $this->commitMasterChanges( __METHOD__ ); // sanity
 157         }
 158
 159         /**
 160          * @see ILBFactory::newMainLB()
 161          * @param bool $domain
 162          * @return LoadBalancer
 163          */
 164         abstract public function newMainLB( $domain = false );
 165
 166         /**
 167          * @see ILBFactory::getMainLB()
 168          * @param bool $domain
 169          * @return LoadBalancer
 170          */
 171         abstract public function getMainLB( $domain = false );
 172
 173         /**
 174          * @see ILBFactory::newExternalLB()
 175          * @param string $cluster
 176          * @return LoadBalancer
 177          */
 178         abstract public function newExternalLB( $cluster );
 179
 180         /**
 181          * @see ILBFactory::getExternalLB()
 182          * @param string $cluster
 183          * @return LoadBalancer
 184          */
 185         abstract public function getExternalLB( $cluster );
 186
 187         /**
 188          * Call a method of each tracked load balancer
 189          *
 190          * @param string $methodName
 191          * @param array $args
 192          */
 193         protected function forEachLBCallMethod( $methodName, array $args = [] ) {
 194                 $this->forEachLB(
 195                         function ( ILoadBalancer $loadBalancer, $methodName, array $args ) {
 196                                 call_user_func_array( [ $loadBalancer, $methodName ], $args );
 197                         },
 198                         [ $methodName, $args ]
 199                 );
 200         }
 201
 202         public function flushReplicaSnapshots( $fname = __METHOD__ ) {
 203                 $this->forEachLBCallMethod( 'flushReplicaSnapshots', [ $fname ] );
 204         }
 205
 206         public function commitAll( $fname = __METHOD__, array $options = [] ) {
 207                 $this->commitMasterChanges( $fname, $options );
 208                 $this->forEachLBCallMethod( 'commitAll', [ $fname ] );
 209         }
 210
 211         public function beginMasterChanges( $fname = __METHOD__ ) {
 212                 if ( $this->trxRoundId !== false ) {
 213                         throw new DBTransactionError(
 214                                 null,
 215                                 "$fname: transaction round '{$this->trxRoundId}' already started."
 216                         );
 217                 }
 218                 $this->trxRoundId = $fname;
 219                 // Set DBO_TRX flags on all appropriate DBs
 220                 $this->forEachLBCallMethod( 'beginMasterChanges', [ $fname ] );
 221         }
 222
 223         public function commitMasterChanges( $fname = __METHOD__, array $options = [] ) {
 224                 if ( $this->trxRoundId !== false && $this->trxRoundId !== $fname ) {
 225                         throw new DBTransactionError(
 226                                 null,
 227                                 "$fname: transaction round '{$this->trxRoundId}' still running."
 228                         );
 229                 }
 230                 /** @noinspection PhpUnusedLocalVariableInspection */
 231                 $scope = $this->getScopedPHPBehaviorForCommit(); // try to ignore client aborts
 232                 // Run pre-commit callbacks and suppress post-commit callbacks, aborting on failure
 233                 $this->forEachLBCallMethod( 'finalizeMasterChanges' );
 234                 $this->trxRoundId = false;
 235                 // Perform pre-commit checks, aborting on failure
 236                 $this->forEachLBCallMethod( 'approveMasterChanges', [ $options ] );
 237                 // Log the DBs and methods involved in multi-DB transactions
 238                 $this->logIfMultiDbTransaction();
 239                 // Actually perform the commit on all master DB connections and revert DBO_TRX
 240                 $this->forEachLBCallMethod( 'commitMasterChanges', [ $fname ] );
 241                 // Run all post-commit callbacks
 242                 /** @var Exception $e */
 243                 $e = null; // first callback exception
 244                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$e ) {
 245                         $ex = $lb->runMasterPostTrxCallbacks( IDatabase::TRIGGER_COMMIT );
 246                         $e = $e ?: $ex;
 247                 } );
 248                 // Commit any dangling DBO_TRX transactions from callbacks on one DB to another DB
 249                 $this->forEachLBCallMethod( 'commitMasterChanges', [ $fname ] );
 250                 // Throw any last post-commit callback error
 251                 if ( $e instanceof Exception ) {
 252                         throw $e;
 253                 }
 254         }
 255
 256         public function rollbackMasterChanges( $fname = __METHOD__ ) {
 257                 $this->trxRoundId = false;
 258                 $this->forEachLBCallMethod( 'suppressTransactionEndCallbacks' );
 259                 $this->forEachLBCallMethod( 'rollbackMasterChanges', [ $fname ] );
 260                 // Run all post-rollback callbacks
 261                 $this->forEachLB( function ( ILoadBalancer $lb ) {
 262                         $lb->runMasterPostTrxCallbacks( IDatabase::TRIGGER_ROLLBACK );
 263                 } );
 264         }
 265
 266         public function hasTransactionRound() {
 267                 return ( $this->trxRoundId !== false );
 268         }
 269
 270         /**
 271          * Log query info if multi DB transactions are going to be committed now
 272          */
 273         private function logIfMultiDbTransaction() {
 274                 $callersByDB = [];
 275                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$callersByDB ) {
 276                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 277                         $callers = $lb->pendingMasterChangeCallers();
 278                         if ( $callers ) {
 279                                 $callersByDB[$masterName] = $callers;
 280                         }
 281                 } );
 282
 283                 if ( count( $callersByDB ) >= 2 ) {
 284                         $dbs = implode( ', ', array_keys( $callersByDB ) );
 285                         $msg = "Multi-DB transaction [{$dbs}]:\n";
 286                         foreach ( $callersByDB as $db => $callers ) {
 287                                 $msg .= "$db: " . implode( '; ', $callers ) . "\n";
 288                         }
 289                         $this->queryLogger->info( $msg );
 290                 }
 291         }
 292
 293         public function hasMasterChanges() {
 294                 $ret = false;
 295                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 296                         $ret = $ret || $lb->hasMasterChanges();
 297                 } );
 298
 299                 return $ret;
 300         }
 301
 302         public function laggedReplicaUsed() {
 303                 $ret = false;
 304                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$ret ) {
 305                         $ret = $ret || $lb->laggedReplicaUsed();
 306                 } );
 307
 308                 return $ret;
 309         }
 310
 311         public function hasOrMadeRecentMasterChanges( $age = null ) {
 312                 $ret = false;
 313                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $age, &$ret ) {
 314                         $ret = $ret || $lb->hasOrMadeRecentMasterChanges( $age );
 315                 } );
 316                 return $ret;
 317         }
 318
 319         public function waitForReplication( array $opts = [] ) {
 320                 $opts += [
 321                         'domain' => false,
 322                         'cluster' => false,
 323                         'timeout' => $this->cliMode ? 60 : 10,
 324                         'ifWritesSince' => null
 325                 ];
 326
 327                 if ( $opts['domain'] === false && isset( $opts['wiki'] ) ) {
 328                         $opts['domain'] = $opts['wiki']; // b/c
 329                 }
 330
 331                 // Figure out which clusters need to be checked
 332                 /** @var ILoadBalancer[] $lbs */
 333                 $lbs = [];
 334                 if ( $opts['cluster'] !== false ) {
 335                         $lbs[] = $this->getExternalLB( $opts['cluster'] );
 336                 } elseif ( $opts['domain'] !== false ) {
 337                         $lbs[] = $this->getMainLB( $opts['domain'] );
 338                 } else {
 339                         $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$lbs ) {
 340                                 $lbs[] = $lb;
 341                         } );
 342                         if ( !$lbs ) {
 343                                 return; // nothing actually used
 344                         }
 345                 }
 346
 347                 // Get all the master positions of applicable DBs right now.
 348                 // This can be faster since waiting on one cluster reduces the
 349                 // time needed to wait on the next clusters.
 350                 $masterPositions = array_fill( 0, count( $lbs ), false );
 351                 foreach ( $lbs as $i => $lb ) {
 352                         if ( $lb->getServerCount() <= 1 ) {
 353                                 // T29975 - Don't try to wait for replica DBs if there are none
 354                                 // Prevents permission error when getting master position
 355                                 continue;
 356                         } elseif ( $opts['ifWritesSince']
 357                                 && $lb->lastMasterChangeTimestamp() < $opts['ifWritesSince']
 358                         ) {
 359                                 continue; // no writes since the last wait
 360                         }
 361                         $masterPositions[$i] = $lb->getMasterPos();
 362                 }
 363
 364                 // Run any listener callbacks *after* getting the DB positions. The more
 365                 // time spent in the callbacks, the less time is spent in waitForAll().
 366                 foreach ( $this->replicationWaitCallbacks as $callback ) {
 367                         $callback();
 368                 }
 369
 370                 $failed = [];
 371                 foreach ( $lbs as $i => $lb ) {
 372                         if ( $masterPositions[$i] ) {
 373                                 // The RDBMS may not support getMasterPos()
 374                                 if ( !$lb->waitForAll( $masterPositions[$i], $opts['timeout'] ) ) {
 375                                         $failed[] = $lb->getServerName( $lb->getWriterIndex() );
 376                                 }
 377                         }
 378                 }
 379
 380                 if ( $failed ) {
 381                         throw new DBReplicationWaitError(
 382                                 null,
 383                                 "Could not wait for replica DBs to catch up to " .
 384                                 implode( ', ', $failed )
 385                         );
 386                 }
 387         }
 388
 389         public function setWaitForReplicationListener( $name, callable $callback = null ) {
 390                 if ( $callback ) {
 391                         $this->replicationWaitCallbacks[$name] = $callback;
 392                 } else {
 393                         unset( $this->replicationWaitCallbacks[$name] );
 394                 }
 395         }
 396
 397         public function getEmptyTransactionTicket( $fname ) {
 398                 if ( $this->hasMasterChanges() ) {
 399                         $this->queryLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 400                                 ( new RuntimeException() )->getTraceAsString() );
 401
 402                         return null;
 403                 }
 404
 405                 return $this->ticket;
 406         }
 407
 408         public function commitAndWaitForReplication( $fname, $ticket, array $opts = [] ) {
 409                 if ( $ticket !== $this->ticket ) {
 410                         $this->perfLogger->error( __METHOD__ . ": $fname does not have outer scope.\n" .
 411                                 ( new RuntimeException() )->getTraceAsString() );
 412
 413                         return;
 414                 }
 415
 416                 // The transaction owner and any caller with the empty transaction ticket can commit
 417                 // so that getEmptyTransactionTicket() callers don't risk seeing DBTransactionError.
 418                 if ( $this->trxRoundId !== false && $fname !== $this->trxRoundId ) {
 419                         $this->queryLogger->info( "$fname: committing on behalf of {$this->trxRoundId}." );
 420                         $fnameEffective = $this->trxRoundId;
 421                 } else {
 422                         $fnameEffective = $fname;
 423                 }
 424
 425                 $this->commitMasterChanges( $fnameEffective );
 426                 $this->waitForReplication( $opts );
 427                 // If a nested caller committed on behalf of $fname, start another empty $fname
 428                 // transaction, leaving the caller with the same empty transaction state as before.
 429                 if ( $fnameEffective !== $fname ) {
 430                         $this->beginMasterChanges( $fnameEffective );
 431                 }
 432         }
 433
 434         public function getChronologyProtectorTouched( $dbName ) {
 435                 return $this->getChronologyProtector()->getTouched( $dbName );
 436         }
 437
 438         public function disableChronologyProtection() {
 439                 $this->getChronologyProtector()->setEnabled( false );
 440         }
 441
 442         /**
 443          * @return ChronologyProtector
 444          */
 445         protected function getChronologyProtector() {
 446                 if ( $this->chronProt ) {
 447                         return $this->chronProt;
 448                 }
 449
 450                 $this->chronProt = new ChronologyProtector(
 451                         $this->memStash,
 452                         [
 453                                 'ip' => $this->requestInfo['IPAddress'],
 454                                 'agent' => $this->requestInfo['UserAgent'],
 455                         ],
 456                         $this->requestInfo['ChronologyPositionIndex']
 457                 );
 458                 $this->chronProt->setLogger( $this->replLogger );
 459
 460                 if ( $this->cliMode ) {
 461                         $this->chronProt->setEnabled( false );
 462                 } elseif ( $this->requestInfo['ChronologyProtection'] === 'false' ) {
 463                         // Request opted out of using position wait logic. This is useful for requests
 464                         // done by the job queue or background ETL that do not have a meaningful session.
 465                         $this->chronProt->setWaitEnabled( false );
 466                 }
 467
 468                 $this->replLogger->debug( __METHOD__ . ': using request info ' .
 469                         json_encode( $this->requestInfo, JSON_PRETTY_PRINT ) );
 470
 471                 return $this->chronProt;
 472         }
 473
 474         /**
 475          * Get and record all of the staged DB positions into persistent memory storage
 476          *
 477          * @param ChronologyProtector $cp
 478          * @param callable|null $workCallback Work to do instead of waiting on syncing positions
 479          * @param string $mode One of (sync, async); whether to wait on remote datacenters
 480          * @param int|null &$cpIndex DB position key write counter; incremented on update
 481          */
 482         protected function shutdownChronologyProtector(
 483                 ChronologyProtector $cp, $workCallback, $mode, &$cpIndex = null
 484         ) {
 485                 // Record all the master positions needed
 486                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $cp ) {
 487                         $cp->shutdownLB( $lb );
 488                 } );
 489                 // Write them to the persistent stash. Try to do something useful by running $work
 490                 // while ChronologyProtector waits for the stash write to replicate to all DCs.
 491                 $unsavedPositions = $cp->shutdown( $workCallback, $mode, $cpIndex );
 492                 if ( $unsavedPositions && $workCallback ) {
 493                         // Invoke callback in case it did not cache the result yet
 494                         $workCallback(); // work now to block for less time in waitForAll()
 495                 }
 496                 // If the positions failed to write to the stash, at least wait on local datacenter
 497                 // replica DBs to catch up before responding. Even if there are several DCs, this increases
 498                 // the chance that the user will see their own changes immediately afterwards. As long
 499                 // as the sticky DC cookie applies (same domain), this is not even an issue.
 500                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $unsavedPositions ) {
 501                         $masterName = $lb->getServerName( $lb->getWriterIndex() );
 502                         if ( isset( $unsavedPositions[$masterName] ) ) {
 503                                 $lb->waitForAll( $unsavedPositions[$masterName] );
 504                         }
 505                 } );
 506         }
 507
 508         /**
 509          * Base parameters to LoadBalancer::__construct()
 510          * @return array
 511          */
 512         final protected function baseLoadBalancerParams() {
 513                 return [
 514                         'localDomain' => $this->localDomain,
 515                         'readOnlyReason' => $this->readOnlyReason,
 516                         'srvCache' => $this->srvCache,
 517                         'wanCache' => $this->wanCache,
 518                         'profiler' => $this->profiler,
 519                         'trxProfiler' => $this->trxProfiler,
 520                         'queryLogger' => $this->queryLogger,
 521                         'connLogger' => $this->connLogger,
 522                         'replLogger' => $this->replLogger,
 523                         'errorLogger' => $this->errorLogger,
 524                         'deprecationLogger' => $this->deprecationLogger,
 525                         'hostname' => $this->hostname,
 526                         'cliMode' => $this->cliMode,
 527                         'agent' => $this->agent,
 528                         'chronologyProtector' => $this->getChronologyProtector()
 529                 ];
 530         }
 531
 532         /**
 533          * @param ILoadBalancer $lb
 534          */
 535         protected function initLoadBalancer( ILoadBalancer $lb ) {
 536                 if ( $this->trxRoundId !== false ) {
 537                         $lb->beginMasterChanges( $this->trxRoundId ); // set DBO_TRX
 538                 }
 539
 540                 $lb->setTableAliases( $this->tableAliases );
 541                 $lb->setIndexAliases( $this->indexAliases );
 542         }
 543
 544         public function setTableAliases( array $aliases ) {
 545                 $this->tableAliases = $aliases;
 546         }
 547
 548         public function setIndexAliases( array $aliases ) {
 549                 $this->indexAliases = $aliases;
 550         }
 551
 552         public function setDomainPrefix( $prefix ) {
 553                 $this->localDomain = new DatabaseDomain(
 554                         $this->localDomain->getDatabase(),
 555                         null,
 556                         $prefix
 557                 );
 558
 559                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( $prefix ) {
 560                         $lb->setDomainPrefix( $prefix );
 561                 } );
 562         }
 563
 564         public function closeAll() {
 565                 $this->forEachLBCallMethod( 'closeAll', [] );
 566         }
 567
 568         public function setAgentName( $agent ) {
 569                 $this->agent = $agent;
 570         }
 571
 572         public function appendShutdownCPIndexAsQuery( $url, $index ) {
 573                 $usedCluster = 0;
 574                 $this->forEachLB( function ( ILoadBalancer $lb ) use ( &$usedCluster ) {
 575                         $usedCluster |= ( $lb->getServerCount() > 1 );
 576                 } );
 577
 578                 if ( !$usedCluster ) {
 579                         return $url; // no master/replica clusters touched
 580                 }
 581
 582                 return strpos( $url, '?' ) === false ? "$url?cpPosIndex=$index" : "$url&cpPosIndex=$index";
 583         }
 584
 585         public function setRequestInfo( array $info ) {
 586                 $this->requestInfo = $info + $this->requestInfo;
 587         }
 588
 589         /**
 590          * Make PHP ignore user aborts/disconnects until the returned
 591          * value leaves scope. This returns null and does nothing in CLI mode.
 592          *
 593          * @return ScopedCallback|null
 594          */
 595         final protected function getScopedPHPBehaviorForCommit() {
 596                 if ( PHP_SAPI != 'cli' ) { // https://bugs.php.net/bug.php?id=47540
 597                         $old = ignore_user_abort( true ); // avoid half-finished operations
 598                         return new ScopedCallback( function () use ( $old ) {
 599                                 ignore_user_abort( $old );
 600                         } );
 601                 }
 602
 603                 return null;
 604         }
 605
 606         function __destruct() {
 607                 $this->destroy();
 608         }
 609 }
 610
 611 class_alias( LBFactory::class, 'LBFactory' );